| 摘要 |
A gas discharge tube of the present invention has an envelope for accommodating an anode (24) for receiving thermoelectrons emitted from a thermionic cathode (25), a focusing electrode (26) for focusing a path of the thermoelectrons from the thermionic cathode to the anode, and a discharge shielding plate (21) consisting of a material having electrical insulating properties, the anode being arranged in contact with one end of the discharge plate, and the focusing electrode being arranged in contact with the other end of the discharge shielding plate. Since the anode and the focusing electrode are arranged in contact with both the sides of the discharge shielding plate consisting of an insulating material such as a ceramic, the positions of these electrodes are held at high accuracy, and the electrical insulating properties therebetween are maintained even at a high temperature during long-time continuous light emission. For this reason, a short circuit between the electrodes and variations in length of a discharge path can be prevented. Therefore, a gas discharge tube having a long service life and a high operational stability during long-time continuous light emission can be provided. <IMAGE> |
